The solution most commonly used to enable two electronic modules to exchange data signals between each other consists in connecting them together with two electrical lines. One of the lines is used for transmitting data signals in one direction, the other for transmitting them in the opposite direction. This solution of course has the disadvantage of necessitating three or even four electrical connections and a length of electrical line of at least equal to twice the distance separating the two modules. In applications where a large number of electronic modules have to exchange data signals between each other, the cost of the electrical lines and their wiring can become prohibitive, while the overall reliability becomes proportionally degraded. This type of problem is particularly encountered on board motor vehicles in which the amount of electrical and electronic equipment has increased considerably during recent years.
It is already known that one answer to this problem is provided by making use of multiplexing. This technique in fact enables two electronic modules to exchange data signals in both directions by means of a single link. In the case of frequency multiplexing, at least one of the two data signals is transmitted by modulation and then demodulation of a carrier, while in time multiplexing, the exchange of data signals is not truly simultaneous but is organized by a line occupancy protocol. However, it is also known that multiplexing is a complex and expensive technique which cannot be directly adapted to an existing electronic architecture and necessitates an entirely new definition of that architecture.
Contrary to this, the invention aims at providing a device for the simultaneous transmission of two data signals over the same electrical line in opposite directions which can be used in replacement of the traditional two-line electrical links with no fundamental reconsideration of the architecture of the electrical or electronic systems concerned.